public class StringDemo{
   public static void main(String[] args){
      String text = "Have a nice day!!:)";
	  System.out.println("orign content:" + text);
	  System.out.println("upper case:" + text.toUpperCase());
	  System.out.println("Lower case:" + text.toLowerCase());
	  System.out.println("Length:" + text.length());
	  System.out.println("Replace:" + text.replaceAll("nice", "good"));
	  System.out.println("Substring:" + text.substring(5));
	 
   }
}